From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from smtp.kernel.org (aws-us-west-2-korg-mail-alma10-1.taild15c8.ts.net [100.103.45.18]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by smtp.subspace.kernel.org (Postfix) with ESMTPS id 7016B3019D8 for ; Thu, 16 Jul 2026 15:37:08 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=100.103.45.18 ARC-Seal:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1784216229; cv=none; b=ZrKiwfOoho9V61hDTw0jHQ6XfWOCanZnHjdlicS5YqYWuPOFMBp2w216hmMGa32ZlvxM5SconZxo/yAjp0FqGjZ0DIbm4L9KdCFC6ho+2GpgJKjo9ysU/6jmTj76Tur+yx+3UOg6U/Yy+JQG4GNcqPoiVOT81HfP/KIFp9IbYSI= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1784216229; c=relaxed/simple; bh=q5eQ4gcu5q1hO5TvSTm2OWEy3qp8Tb53R5WP+yQdhPs=; h=From:To:Cc:Subject:Date:Message-ID:In-Reply-To:References: MIME-Version; b=ILiyUznNoxJMLJsIXFCBZokMgENmBq0TsacsN4r+FxBLj2VA5K8uI5VKAXAxrxUpr0hiJkCreqbgmN5dqvsYTe4NLJIfkgLzpOK1ckz30aF8vVWrDLUamn1ysTqFidwULCtPjAFKVPDPcnGmt+LHryEmRV5kAPQyRwJ0u8HN5Jc= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=kernel.org header.i=@kernel.org header.b=nEdqMtEB; arc=none smtp.client-ip=100.103.45.18 Authentication-Results: smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=kernel.org header.i=@kernel.org header.b="nEdqMtEB" Received: by smtp.kernel.org (Postfix) with ESMTPSA id 6A6071F00A3A; Thu, 16 Jul 2026 15:37:07 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=kernel.org; s=k20260515; t=1784216228; bh=8h/ygwnu8MbGX7+0ydI71uS5Plg6w4pVYz9yJ+MsJSQ=; h=From:To:Cc:Subject:Date:In-Reply-To:References; b=nEdqMtEB8yJxcGntxZahXluo1/3/A+JtxXwvt731FZ4/bBs+bDBfxzB7+32+BOiqx dvc2ecF5Ai3GuN3YrvjpbsacOF38RvHMJR1VGcABOQ61QyifpowLL5woXl7YCF1kYs et2IbDSDFiarlj3Cnc1A0FyDlPar7HKIS/IGMJeHB7Qi/BT6tOH7WOZAtEoOa6g7ic ZpolvhIA96tuFP/apwvR9AgwG/xSQaacEet+/8+oITV3+48XZmA+CFzL1hDB6TBXMZ 1Je5drb1rgiVffeXKKMeZ/dmPWVSU48JpW+HeUFsWW4Gt6EHZVbJPq/mFNDfBPXoO8 Esfs86mj2EABQ== From: Sasha Levin To: stable@vger.kernel.org Cc: Namjae Jeon , munan Huang , ChenXiaoSong , Steve French , Sasha Levin Subject: [PATCH 6.1.y 3/7] ksmbd: fix use-after-free in __ksmbd_close_fd() via durable scavenger Date: Thu, 16 Jul 2026 11:37:00 -0400 Message-ID: <20260716153704.583869-3-sashal@kernel.org> X-Mailer: git-send-email 2.53.0 In-Reply-To: <20260716153704.583869-1-sashal@kernel.org> References: <2026071414-kosher-parsley-920b@gregkh> <20260716153704.583869-1-sashal@kernel.org> Precedence: bulk X-Mailing-List: stable@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Transfer-Encoding: 8bit From: Namjae Jeon [ Upstream commit 235e32320a470fcd3998fb3774f2290a0eb302a1 ] When a durable file handle survives session disconnect (TCP close without SMB2_LOGOFF), session_fd_check() sets fp->conn = NULL to preserve the handle for later reconnection. However, it did not clean up the byte-range locks on fp->lock_list. Later, when the durable scavenger thread times out and calls __ksmbd_close_fd(NULL, fp), the lock cleanup loop did: spin_lock(&fp->conn->llist_lock); This caused a slab use-after-free because fp->conn was NULL and the original connection object had already been freed by ksmbd_tcp_disconnect(). The root cause is asymmetric cleanup: lock entries (smb_lock->clist) were left dangling on the freed conn->lock_list while fp->conn was nulled out. To fix this issue properly, we need to handle the lifetime of smb_lock->clist across three paths: - Safely skip clist deletion when list is empty and fp->conn is NULL. - Remove the lock from the old connection's lock_list in session_fd_check() - Re-add the lock to the new connection's lock_list in ksmbd_reopen_durable_fd(). Fixes: c8efcc786146 ("ksmbd: add support for durable handles v1/v2") Co-developed-by: munan Huang Signed-off-by: munan Huang Reviewed-by: ChenXiaoSong Signed-off-by: Namjae Jeon Signed-off-by: Steve French Stable-dep-of: c1016dd1d8b2 ("ksmbd: track the connection owning a byte-range lock") Signed-off-by: Sasha Levin --- fs/smb/server/vfs_cache.c | 8 +++++--- 1 file changed, 5 insertions(+), 3 deletions(-) diff --git a/fs/smb/server/vfs_cache.c b/fs/smb/server/vfs_cache.c index 2528ce8aeebbef..65dd85668cee24 100644 --- a/fs/smb/server/vfs_cache.c +++ b/fs/smb/server/vfs_cache.c @@ -317,9 +317,11 @@ static void __ksmbd_close_fd(struct ksmbd_file_table *ft, struct ksmbd_file *fp) * there are not accesses to fp->lock_list. */ list_for_each_entry_safe(smb_lock, tmp_lock, &fp->lock_list, flist) { - spin_lock(&fp->conn->llist_lock); - list_del(&smb_lock->clist); - spin_unlock(&fp->conn->llist_lock); + if (!list_empty(&smb_lock->clist) && fp->conn) { + spin_lock(&fp->conn->llist_lock); + list_del(&smb_lock->clist); + spin_unlock(&fp->conn->llist_lock); + } list_del(&smb_lock->flist); locks_free_lock(smb_lock->fl); -- 2.53.0